Introduction

The appearance of the mid-face – in particular the periorbital region – marks the cornerstone of facial attractiveness, an important factor in social and interpersonal interactions. As ‘window to the soul’, the eye can express a variety of emotions and is one of the most compelling features of any face. The use of botulinum toxin (BoNT) in the periocular area has a long history; indeed, the discovery of the toxin’s benefits were first noted in patients treated for strabismus and blepharospasm, and it has since been used therapeutically in the eyelid for the treatment of numerous other blepharospastic conditions and systemic diseases affecting the periorbital area, such as facial palsies and lid retraction in thyroid ophthalmopathy. Since then, BoNT has become an important part of the armamentarium for the cosmetic or functional improvement of the periorbital area, alone or in combination with other rejuvenating modalities. However, treatment in the upper and lower lids – the thinnest skin in the human body – requires an in-depth understanding of anatomy and the aging process, appropriate patient selection, and careful attention to individualized treatment.

Anatomy of the eye

Complete knowledge and understanding of both dynamic and volumetric changes in the face, as well as the interaction between and function of various facial musculature and the surrounding soft tissue, are critical to ensuring successful outcomes with the use of BoNT in the periorbital region. Although in-depth examinations of facial anatomy have been published elsewhere, this chapter focuses on the anatomy of the eye relevant to the use of BoNT in the upper and lower eyelids (Fig. 16.1).

Figure 16.1 Periorbital anatomy.

The upper eyelid extends from the eyelid margin to the eyebrow superiorly, with the superior palpebral sulcus (associated with the upper eyelid skin crease) located lengthwise between the medial canthus and the lateral orbital rim, approximately in the range of 8–11 mm superior to the eyelid margin. The lower eyelid extends below the inferior orbital rim to join the cheek. In youth, the inferior palpebral sulcus (lower eyelid fold) is located 3–5 mm from the lower lid margin.

The orbicularis oculi – the sphincter muscle of the eyelids – is a wide, concentric band of muscle comprising the palpebral component, which can be further divided into pretarsal and preseptal portions and is responsible for blinking and gentle eyelid closure, and the orbital component, responsible for forceful lid closure and the production of lateral canthal and lower eyelid rhytides. Superiorly, the orbital component interdigitates with other superficial muscles of facial expression, including the frontalis, corrugator, and the depressor supercilii muscles, laterally it comes into proximity of the overlying fascia of the temporalis muscles, and the muscles of the inferior quadratus labii superioris and zygomaticus complex. Inferiorly, the orbicularis lies flat across the cheek and is considered a part of the superficial musculoaponeurotic system (SMAS), which translates muscle movement into movement of the skin. At the junction of the lower lid with the cheek, the orbicularis oculi muscle forms a direct attachment with the orbital rim at the junction of the palpebral and orbital portions.

Periorbital aging

Aging in the face is most prominent in the mid-facial and periorbital regions, due to both dynamic and volumetric changes. Bony changes and atrophy of subcutaneous soft tissues lead to a loss of cutaneous support, muscles become lax, and skin that was once smooth and youthful becomes rough and dry with irregular pigmentation and uneven texture. As the skin repositions itself over the changing landscape of the face, wrinkles and fine lines begin to appear and become prominent as dynamic turns to static.

Eyelid skin is the thinnest on the body (<1 mm), with sparse underlying subcutaneous fat. Over time, the delicate lids are prone to further thinning and stretching by too-vigorous rubbing or surgical procedures to rejuvenate the area. The lower lid is subject to fat redistribution, laxity, and weakening of the connective tissue. The normally smooth transition from lower lid to cheek becomes more prominent, with puffiness, dark circles, or dermatochalasis under the eye. Orbital laxity, atrophy, and pseudoherniation give the impression of a sunken eye, while radial wrinkles appear on the lateral aspect of the orbit.

Patient assessment and selection

Because successful use of BoNT in the periorbital region demands close attention to anatomical variations and individualized treatment, a thorough evaluation of every patient is mandatory. Comprehensive assessment will include patient education and counseling, medical history, and physical examination of the periorbital region and area to be treated.

Communication between patient and clinician builds trust and ensures that expectations do not exceed realistic outcomes. Evaluation of periorbital concerns in discussion as well as physical examination will avoid post-injection problems. Interviews should address the patient’s current ophthalmic status including the presence of dry eye symptoms as well as the transient nature of BoNT injections, the need for frequent touch-ups, common injection-related side effects, and potential complications. Informed consent is essential.

A complete medical and ophthalmic history is necessary, including previous experiences with rejuvenation procedures, surgery, and any other conditions that might influence treatment plans or outcome. The degree of rhytides and their potential response to treatment can be assessed via the Glogau photoaging scale (Table 16.1). Moreover, the quality of skin around the eye will also determine a treatment plan: patients with excessive skin above the eye, prominent fat pads in the lower lid, septal fat herniation, or severe elastosis (identified by a positive snap test), may require additional rejuvenating procedures such as laser or light-based therapies or even surgery prior to augmentation. All findings (including any sign of ptosis or asymmetry) should be noted and discussed with the patient, and standard digital photographs taken both before and after any treatments. Photographs should display the face in repose and at maximal expression to document changes on animation.

Table 16.1 Wrinkle severity and rejuvenation requirements

^* Based on the Glogau classification of photoaging.

Not everyone is a candidate for BoNT therapy. Aside from general contraindications (Box 16.1), caution should prevail in patients with a history and especially complications related to previous lower eyelid blepharoplasty and injections avoided in patients with lower lid laxity, due to the risk of scleral show, pre-existing conditions that could be worsened by treatment, such as mid-facial paresis or symptomatic dry eyes, stable or progressive muscular dystrophic conditions causing blepharoptosis, or anyone with already-compromised function of the orbicularis oculi.

Indications and techniques

Consensus recommendations have been developed for dosing and techniques in all areas of the face, although treatment must be individualized according to muscle size and function and desired outcome. In the upper and lower lid, precise placement of injections and conservative doses are crucial in avoiding adverse effects and obtaining the most beneficial effects.

Hypertrophic orbicularis, infraorbital rhytides, and widening of the eye

Infraorbital rhytides radiating below the eyes toward the cheek arise from concentric contraction of the orbicularis oculi peripheral to the lines. Moreover, such hypertrophy of the pretarsal portion of the orbicularis oculi contributes to the perception of lower eyelid bags (a ‘jelly roll’ appearance) and a narrowing of the palpebral aperture, particularly when the patient smiles. A series of studies conducted by Flynn & Carruthers have shown that 2 U BoNT placed subdermally in the lower eyelid in the midpupillary line, 3 mm below the ciliary margin (Fig. 16.2) can relax and flatten the pretarsal orbicularis, improving the appearance of the lower lid. Similar injections in the lower lid with concomitant treatment of the lateral canthal rhytides (three injections of 4 U each, for a total of 12 U) can produce increases of approximately 2–3 mm in the vertical palpebral aperture at rest and full smile, respectively, giving the lower eyelid a more rounded appearance (Fig. 16.3). Further examination by Flynn & Carruthers demonstrated a clear dose response when the lower lid was treated alone; however, higher doses led to an increase in side effects and did not further enhance the size of the palpebral aperture. The authors therefore recommend a conservative approach with the smallest dose (1–2 U at two sites) in the lower lid, with retreatment after 2–4 weeks if necessary.

Figure 16.2 Flattening of hypertrophic orbicularis oculi and widening of the palpebral aperture following 2 U BoNT-A mid-pupillary line 3 mm inferior to lash margin: (A) before, (B) after, and (C) injection technique.

Figure 16.3 Improvement of rhytides and widening of palpebral aperture: (A) before and (B) after 2 U BoNT (Botox^®) under the eye and 12 U in the lateral canthal rhytides.

Case Study 1 (see Fig. 16.2)

A healthy 32-year-old Filipino-Canadian woman presented complaining of a ‘jelly roll’ underneath her eyes when she smiled. She requested a more western wide-eyed look and reduction of the ‘jelly roll’. Figure 16.2A demonstrates a hypertrophic orbicularis oculi. A ‘snap-test’ demonstrated excellent elasticity, which, in conjunction with the youthful tone and texture of the skin, indicated that the patient was a suitable candidate for infraorbital BoNT-A treatment. In order to achieve a wider aperture and flattening of hypertrophic orbicularis oculi (Fig. 16.2B) 2 U of BoNT-A were injected in the mid-pupillary line 4 mm below the lid margin bilaterally. Figure 16.2C demonstrates the injection site and technique.

Lid ptosis, malposition, and asymmetry

BoNT is an effective treatment for the temporary management of mild-to-moderate upper lid ptosis, malposition, and eyelid-fissure asymmetry. Research by Fagien indicates that correct placement, dosing, and careful patient selection will determine predictability of response. Typically, eyelid malposition of any etiology has been treated by surgical correction of the underlying cause, with nonsurgical options for upper lid ptosis limited to adrenergic topical ophthalmic drops. Low-dose subdermal injection of BoNT (0.5–1.5 U) into the extreme medial and lateral aspects of the pretarsal region of the orbicularis just above the lash line (Figs 16.4 and 16.5) allows unopposed activity of the levator palpebrae and Müller’s muscle, and a return to symmetry.

Figure 16.4 Upper eyelid ptosis: (A) before and (B) after treatment at the extreme medial and lateral aspects of the pretarsal region (injection sites marked by blue dot).

Figure 16.5 Injection pattern for correction of upper lid ptosis (injection sites marked by blue dot).

Likewise, lower lid asymmetry and malposition (such as retraction, ectropion, and entropion) have historically been treated with surgical intervention to tighten or shorten the horizontal length of the lower eyelid to achieve symmetry with the contralateral side. Malposition and symmetry can be restored to the lower eyelid by weakening the lower lid elevators on the side opposite the lower lid retractions by two injections of BoNT: one placed at the extreme lateral aspect of the lower eyelid, the other at the mid aspect of the lower eyelid pretarsal region, located approximately mid-pupil, inducing a similar, retracted effect.

Doses in the upper and lower lids range from 0.5 to 1.5 U per injection site, with higher doses reserved for cases of lower eyelid hypertrophy and severe ptosis, or when changing the position of the lower eye.

Adjunctive treatments for the lid

Increasingly, each aspect of facial rejuvenation is viewed as a whole, using combination therapies to provide the best possible outcomes. There are a variety of treatments aimed at improving the appearance of the eye that can be used in combination with BoNT for a synergistic effect, targeting not only improvement in rhytides but also in pigmentation, texture, scarring, and laxity.

Adverse events

Bruising and ecchymosis are the most common injection-site reactions to BoNT in the periorbital area. The addition of sublingual Arnica montana immediately following and then four times a day for 2–3 days may minimize bruising, as will superficial injections and the application of ice immediately following treatment.

More serious adverse effects can occur, usually due to inappropriate dosing or injection technique (Table 16.2). Some patients describe a temporary feeling of ‘fullness’ in the lower lid following treatment. In rare cases, but particularly in patients with excessive lower lid laxity, this may manifest as edema that is worse in the morning. It is believed that this results from inactivity of the orbicularis oculi, which aids in the drainage of lymphatic fluid. Rare complications in the periocular area include lower eyelid laxity, scleral show, epiphora, ectropion, diplopia, dry eye, incomplete eyelid closure, and ptosis. Careful patient selection and attention to anatomical features of the periorbital region can aid in avoiding most of these side effects, all of which eventually disappear over time due to the transient effect of BoNT. Goldman reported a case of prominent festoon formation after 2 U 2–3 mm below the ciliary margin in the mid-pupillary line and 10 U (single injection) in the mid-lateral canthal region. Only at the follow-up visit did the patient admit to a previous facelift, forehead lift, and lower eyelid blepharoplasty 8 years previously. This case scenario emphasizes the importance of pre-treatment history and physical examination of the lower eyelid structure and function before treatment with even small doses of BoNT. Upper eyelid complications can also be avoided by careful thought, injection technique, and placement. Mild lagophthalmos can be induced in the upper eyelid by greater than necessary dosages and can generally be avoided with doses less than 1.5 U. This too, stresses the need for an initial conservative approach that can be titrated to the most effective dose.

Table 16.2 Injection-related complications

Administering injections peripheral to the orbital rim and using a higher concentration and smaller volume may also avoid infiltration of the toxin into the vicinity of the extraocular muscles. Avoiding the pretarsal region (and choosing the lateral preseptal area) for the treatment of lower lid rhytides will both improve the aesthetic effect and decrease the likelihood of functional adverse effects and malposition.

Conclusion

The aim of rejuvenation to the infraorbital eye involves targeting fine lines and wrinkles and restoring harmony and balance that may have been lost in the aging process. BoNT injections can achieve that goal, alone or in combination with other cosmetic procedures or applications around the eye, with certain caveats: the injecting clinician must have an in-depth awareness of functional anatomy and the interplay of muscles of facial expression, and careful screening of patients must occur prior to any treatment. Many of the more serious adverse events can be attributed to misplaced injections, poor technique, or inappropriate patient selection.